In the case of an electric motor-actuated brake device, a clamping force is preferably produced by means of a spindle-nut system, wherein the spindle-nut system is preferably disposed in a brake piston. Because of the electromechanical actuation and the design-related mechanical transmission by means of gear stages, a brake device of this type has longer application times for clamping and release processes, in particular compared to purely hydraulic brake devices. In this case, in particular occur it can that the time to build up a clamping force is in conflict with a rapid start-up demand by a driver of a vehicle. As an example, in order to show the potential of said method, a so-called racing start can be considered that is to be carried out from a standstill, starting from a state with a clamped electric motor-actuated parking brake device. The parking brake must then be actuated in the release direction before the vehicle can pick up speed. In particular, in the case of powerful vehicles, or in the case of electrically powered vehicles in which the start-up torque is built up rapidly or already available with the motor at rest, the start-up torque can be available before the holding force of the parking brake has decreased.
It appears that a main reason for the comparatively slow release of an electric motor-actuated brake device is that systems of this type are designed to be self-locking and experience a high level of friction because of the clamping force, so that a build-up of the revolution rate of the electric motor takes place under comparatively high load, wherein a no-load revolution rate can only be reached relatively late. It is known from WO 2005/073043 A1 to relieve the load on a first electric motor-actuated brake device by activating a second, hydraulically actuated brake device, and thus to enable improved release of the first brake device. With a procedure of this type however, a desired hydraulic pressure is first fully built up before the electric motor-actuated brake device is actuated in the release direction. This again costs time, which delays the release process.